Dyed textile fiber and process for producing the same



Jan. 12, 1960 M. T. BARNHILL 2,920,932

DYED TEXTILE FIBER AND PROCESS FOR PRODUCING THE SAME Filed Nov. 8, 1955 INVENTOR.

= MaHh aw T Bfifnhill DYED TEXTILE FIBER .AND. PROCESS FOR PRODUCING THE SAME Matthew T. Barnhill, Sylacaug a, Ala.,- assignor to Avondale Mills, Inc., a corporation of Alabama Application November 8, 1955, Serial No. 545,632

4 Claims. on. 8-28) This invention relates to a'dyed textile fiber and the process for producing the same and more particularly to the dyeing of vegetable type or cellulosic fibers, such as cotton and mixtures of cotton and other fibers.

The primary object of my invention is to provide improved means for dyeing vegetable type textile fibers with indigo dye whereby the indigo penetrates the fibers to produce a uniform color throughout.

A more specific object of my invention is to provide an improved product comprising textile fibers of the vegetable type having applied thereto a fast color bottom of a substantive vat dye and a top dye of indigo.

A still further object of my invention is to provide a process and product of the character designated in which the rich blue color of indigo is obtained throughout the fiber at a minimum of cost and in which the process can be carried out in conventional type dyeing apparatus.

As is well known in the art to which my invention relates, indigo dye has very little affinity for vegetable type fibers, such as cotton. Accordingly, indigo dye is applied to cotton yarns or mixtures of cotton and other fibers by a series of dips into the prepared dye stuff. The fiber being dyed is transferred through a skying arrangement after each dip to oxidize or fix the color onto the fiber. With this process of dyeing cotton fiber, the indigo dye does not penetrate the fiber completely but only dyes the outer portions thereof. Fabrics woven from such dyed fiber, when subjected to rough wear, develop scuff marks and irregular worn zones much lighter in color than the original fabric due to the fact that the outer surface to which the dye is applied wears away by abrasion and thus exposes the undyed under surface. In an attempt to improve the penetration of indigo dye into the fiber, such as cotton yarn, much research has been done and various processes have been tried. Also, other dyes have been substituted for indigo. However, such processes and dyes with which I am familiar have been unsatisfactory due to the fact that they do not produce the rich blue color of indigo which is so much desired. Furthermore, the proposed substitutes for indigo dye are so expensive that it is not economical to use the same. This is particularly true in view of the fact that denim, the predominant fabric dyed with indigo, is quite competitive and must remain a low cost fabric.

Apparatus which may be employed to carry out my improved process is illustrated in the accompanying drawing, forming a part of this application, in which:

Fig. 1a is a diagrammatic view, broken away, and showing a portion of the apparatus; and,

Fig. 1b is a diagrammatic view, showing a continuation of the apparatus shown in Fig. 1a.

Referring now to the'drawing for a better understanding of my invention, I show the yarn in the form of ball warps 10 passing from a creel 11 into dye padders 12 and 13. Positioned between the padders 12 and 13 are squeeze rolls 14. The dye solution in padders 12 and 13 is preferably in the form of a substantive vat dye whereby a fast color bottom is applied to the yarn as 'it passes 2 therethrough. An example of .'a substantive vat dye is Hydron Blue, an Indophenol sulphurized-vat dyestufi, Colour Index 969, A.A.T.C.C. This vat dye is also sold under the trademarks Sulfanthrene Blue and So-Dye- Vat-Blue." Preferably, a relatively light bottom of the dye is applied to the yarn in the padders 12 and 13. The amount of dye applied as a bottom would, of course, vary at the discretion of the dyer so that the desired shade or color could be obtained I have found in actual practice, that a bottom application of from to 50% of the total color value to be appliedis satisfactory in every respect.

After the application of the fast color bottom in padders 12 and 13, the yarn passes through squeeze rolls 16. The dye thus applied is fixed by passing the yarn through asteamer 17, squeeze rolls 18, skying apparatus 19 and wash boxes 21. Positioned between adjacent wash boxes with indigo dye, the fibers are dyed throughout.

21 are squeeze rolls 22.

After the bottom dye has been fixed, the yarnis passed through a series of dye padders 23 which are separated by squeeze rolls 24 and skying apparatus indicated at 26. The dye solution placed in padders 23 may be indigo, Colour Index 1177, A.A.T.C.C. As is well known in the art, indigo, Color Index 1177, A.A.T.C.C., is indigo blue C H N O The yarn is thus top dyed with indigo by dipping the yarn in each of the series of dye padders 23.

Following each dip the yarn is passed through the squeeze rolls 24 and skying apparatus 26 whereby oxidation takes place. The quantity of indigodye required in the padders 23 is dependent upon the deepness of the blue shade desired. After top dyeing with indigo, the yarn is passed through a series of wash boxes 27. Positioned between the wash boxes 27 are squeeze rolls 28. After thus applying and fixing the indigo dye the yarn then passes over the conventional type drying cans indicated generally at 29 and finally to suitable coilers, not shown, thereby completing the process.

As an alternative for the Hydron Blue dye employed in padders 12 and 13, I may employ Naphthol A.S. (pro totype 302, A.A.T.C.C.) which, as is well known, is the anilide of 3-hydroxy Z-naphthoic acid, coupled with Diazo Fast Dark Blue R. I have also found in actual practice that a bottom application of this dye in an amount of from 20% to 50% of the total color value to be applied is satisfactory in every respect. This process is carried out by placing the Naphthol A.S. in the dye padder 12 and placing the Diazo Fast Dark Blue R in the dye padder 13. The fiber is thus first impregnated With the Naphthol A.S. in padder 12 and then passes into padder 13 where the Naphthol A.S. is coupled with the Diazo Fast Dark Blue R to form the color within the fiber. With the bottom dye thus applied, the yarn is next passed through an alkali bath in the manner Well understood and through the skying apparatus 19 and wash boxes 21 to fix the bottom dye. The steamer 17 may thus be eliminated. In all other respects the process is the same as that employed with Hydron Blue. That is, the yarn is top dyed with indigo as it passes through the padders 23, the squeeze rolls 24 and the skying apparatus 26. The yarn next passes through the wash boxes 27 and the squeeze rolls 28 and then to the drying cans 29 as described heretofore.

To improve the penetration and color yields of the dyes employed, penetration agents may be added thereto. Suitable penetration agents may be alkylaryl sulfonate, cellulose sulfite waste liquor, monosodium phosphate, sodium nitrite and crystal urea.

From the foregoing, it will be seen that I have devised an improved dyed fiber and process for producing the same. By first applying a relatively light bottom of a fast blue dye and setting the same and then top dyeing The 3 desired shade of dark blue is thus obtained throughout the fiber or yarn. Accordingly, should the outer surface of the yarn be worn away by abrasion, the undersurface presented would also be of the desired shade of dark blue, thereby preventingthe formation of scufi'ii'iarks and irregular areas of lighter'shades.

While [do not know just why, in my improved process the dye penetrates the fiber only after the application and fixing of the bottom dye as described heretofore, I have found in actual practice that such does take place when cotton yarn and the like are dyed in accordance with my improved process.

I Wish it to be understood that Ido not desire to be limited to the precise examples herein disclosed for obvious modifications will'occur to a person skilled inthe art.

What I claim is:

1. In an article of manufacture, cotton fiber having applied thereto a bottom dye of an indophenol sulphuriz'ed va-t dyestuff, and a top dye of indigo blue.

2. An article of manufacture as defined in claim 1 in which the bottom dye comprises from 20% to 50% of the total dye applied.

3. In a process for dyeing cotton fibers, the steps which comprise applying a relatively light bottom of an indophenol sulphurized-vat dye to said fibers, fixing said indophenol sulphurized-vat dye, top dyeing said fibers with indigo blue dye, and fixing said indigo blue dye.

4. A process for dyeing cotton fibers as defined in claim 3 in which the bottom applied to the fiber comprises from 20% to 50% of the total dye applied.

References Cited in the file of this patent UNITED STATES PATENTS 129,753 SCH-.13. July'23, 1872 1,828,592 Bommer etal. Oct. 20, 1931 1,858,632 Maennchen et a1 May 17, 1932 OTHER REFERENCES Knecht: Manual of Dyeing, 9th ed., pub. by Maple- 20 ton House, Brooklyn, N.Y., vol. I, pp. 322 and 326 relied on. 

1. IN AN ARTICLE OF MANUFACTURE, COTTON FIBER HAVING APPLIED THERETO A BOTTOM DYE OF AN INDOPHENOL SULPHURIZED VAT DYESTUFF, AND A TOP DYE OF INDIGO BLUE. 